If you play a lot of media files from different sources, or go to web sites off the beaten path that have video and sound that you want to play, you might get an error that you don’t have the necessary codec to play the file. What does that mean, and what do you do?
First: a codec is a program that encodes and decodes sound and video files. Hence the word COder DECoder. In the old days (when I used to configure video conferencing systems in the 1980s), codecs were expensive hardware devices. These days, they’re little programs that run on your computer behind the scenes, but Windows still considers them to be hardware. That’s why they’re listed in the Device Manager screen in System Properties.
Windows Media Player should download codecs automatically, when needed. If it doesn’t find what you need, you can search for codecs at Microsoft’s download center. Codecs are also available from other well-known publishers, like Adobe, Apple and others. Or if you know the FourCC number of the codec you need, you can Google it.
But downloading codec packs is a very bad idea. Codec packs are collections of many codecs bundled together, so — in theory — you don’t have to hunt for them individually. There are a lot of them around and most are free, but many codecs in these packs tend not to be properly tested, and this causes system instability that can be hard to diagnose and fix. You might get the short term benefit of being able to play a video, but the longer term headaches often aren’t worth it. Download codecs only from known, trusted sources. These should be digitally signed by the manufacturer.